Phased array spread spectrum system and method

ABSTRACT

A phased array spread spectrum system for maximizing signal strength of a spread-spectrum signal with multipath through the use of receiving means, delaying means, combining means, despreading means, generating means, storing means and comparing means. The receiving means receives a plurality of spread-spectrum signals and a plurality of phased versions of the plurality of spread-spectrum signals. The delaying means delays the received plurality of spread-spectrum signals with respect to the plurality of phased versions of the plurality of spread-spectrum signals by a plurality of delays. The combining means combines the delayed spread-spectrum signals and the plurality of phased versions of the plurality of spread-spectrum signals as a plurality of combined signals. The despreading means despreads the plurality of combined signals as a plurality of despread signals. The generating means generates a plurality of magnitude values from the plurality of despread signals. The storing means stores a plurality of previous-magnitude values previously generated by the generating means and a plurality of present magnitude values presently generated by the generating means. The comparing means compares the previous-magnitude values and the present-magnitude values and, responsive to the comparison, outputs a plurality of comparison signals. The delaying means responds to the plurality of comparison signals by lengthening or shortening the plurality of delays.

RELATED PATENTS

This patent stems from a continuation application of parent applicationhaving Ser. No. 08/625,254, filed Apr. 1, 1996, now U.S. Pat. No.5,633,889 with issue date May 27, 1997, which is a continuationapplication of Ser. No. 08/266,769, filed Jun. 28, 1994, now U.S. Pat.No. 5,659,572 with issue date Aug. 19, 1997, which was acontinuation-in-part application of patent application entitled, PHASEDARRAY SPREAD SPECTRUM SYSTEM AND METHOD, having Ser. No. 08/155,173, andfiling date Nov. 22, 1993, now U.S. Pat. No. 5,422,908 with issue dateJun. 6, 1995. The benefit of the earlier filing date of the parentpatent applications is claimed for common subject matter pursuant to 35U.S.C. § 120.

BACKGROUND OF THE INVENTION

The present invention relates to spread-spectrum communications and moreparticularly to a method and apparatus for enhancing communications byusing phased array principles for increasing signal-to-noise ratio for aspread spectrum signal with multipath arriving at a receiver.

DESCRIPTION OF THE RELEVANT ART

Achieving sufficient signal strength when a received signal comes fromtwo paths is a problem when communicating with spread-spectrummodulation in a multipath environment. The received signal from the twopaths may have phase cancellation, yielding no reception, or receptionwith an unacceptable error rate.

Phased arrays, as is well known in the art, require N antenna elementsfor distinguishing up to N-1 signals arriving at the phased array fromdifferent paths or directions. This concept of spatial diversity is welldeveloped in antenna theory.

SUMMARY OF THE INVENTION

A general object of the invention is an improved system and method forreceiving spread-spectrum signals in a multipath environment.

Another object of the invention is to increase the receivedsignal-to-noise ratio or reduce the probability of error of aspread-spectrum signal arriving from two or more paths.

Another object of the invention is to receive a plurality ofspread-spectrum signals arriving at the antenna from a multiplicity ofdifferent directions, independent of the number of antenna elements.

According to the present invention, as embodied and broadly describedherein, a phased array spread-spectrum system is provided comprisingreceiving means, delaying means, combining means, despreading means,generating means, storing means, and comparing means. The receivingmeans receives a plurality of spread-spectrum signals and a plurality ofphased versions of the plurality of spread-spectrum signals. Typically,the plurality of spread-spectrum signals is received by a firstplurality of receivers coupled to a first antenna, and the plurality ofphased versions of the plurality of spread-spectrum signals is receivedby a second plurality of receivers coupled to a second antenna. Theplurality of received spread-spectrum signals and the plurality ofphased versions of the plurality of spread-spectrum signals aredigitized. The delaying means can delay the plurality of receivedspread-spectrum signals with respect to the plurality of phased versionsof the plurality of spread-spectrum signals by a plurality of delays.The plurality of received spread-spectrum signals consequently becomes aplurality of delayed signals.

The combining means combines the plurality of delayed signals and theplurality of phased versions of the plurality of spread-spectrum signalsas a plurality of combined signals. An in-phase component of eachdelayed signal is combined with an in-phase component of each phasedversion of each spread-spectrum signal, respectively. A quadrature-phasecomponent of each delayed signal is combined with a quadrature-phasecomponent of each phased version of each spread-spectrum signal,respectively.

The despreading means despreads the plurality of combined signals as aplurality of despread signals. This may be accomplished using aplurality of product detectors with a plurality of chipping sequencesmatched to the plurality of received spread-spectrum signals,respectively, or a plurality of matched filters having a plurality ofimpulse functions matched to the plurality of chipping sequences of theplurality of received spread-spectrum signals, respectively.

The generating means generates from the plurality of despread signals aplurality of magnitude values. Each magnitude value may be an absolutevalue, or the square of the in-phase component and quadrature-phasecomponent of the despread signal.

The storing means stores a plurality of previous-magnitude valuespreviously generated by the generating means and a plurality ofpresent-magnitude values presently generated by the generating means.The plurality of previous-magnitude values and the plurality ofpresent-magnitude values, respectively, are compared by the comparingmeans. In response to the result of this comparison, the comparing meansoutputs a plurality of comparison signals. The delaying means may changeany or all of the plurality of delays based on the plurality ofcomparison signals, respectively.

The present invention also includes a method for maximizing the signalstrength of a plurality of spread-spectrum signals with multipathcomprising the steps of receiving the plurality of spread-spectrumsignals and a plurality of phased versions of the plurality ofspread-spectrum signals. The received plurality of spread-spectrumsignals is delayed with respect to the plurality of phased versions ofthe spread-spectrum signals by a plurality of delays, to generate aplurality of delayed signals. The plurality of delayed signals and theplurality of phased versions of the plurality of spread-spectrum signalsare combined as a plurality of combined signals, and the plurality ofcombined signals is despread as a plurality of despread signals,respectively.

The method includes generating a plurality of magnitude values from theplurality of despread signals, and storing a plurality ofprevious-magnitude values and a plurality of present-magnitude values.The plurality of previous-magnitude values and the plurality ofpresent-magnitude values are compared, and a plurality of comparisonsignals is output based on this comparison. Using the plurality ofcomparison signals, the plurality of delays is changed. The step ofgenerating the plurality of magnitude values is a way of locating amaximum. Other procedures for locating a maximum or equivalent may beused.

Additional objects and advantages of the invention are set forth in partin the description which follows, and in part are obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention also may be realized and attained bymeans of the instrumentalities and combinations particularly pointed outin the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate preferred embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIG. 1 is a block diagram illustrating the general concept of theinvention;

FIG. 2 shows two multipath signals being received by a user;

FIG. 3 is a block diagram for adjusting a phase between two receivers;

FIG. 4 is a block diagram for adjusting a phase for a plurality ofspread-spectrum signals; and

FIG. 5 is a block diagram for adjusting a phase between two sets ofreceivers for a plurality of spread-spectrum signals.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference now is made in detail to the present preferred embodiments ofthe invention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals indicate like elementsthroughout the several views.

Handset

The present invention provides a unique phased array spread-spectrumsystem comprising receiving means, delaying means, combining means,despreading means, generating means, storing means, and comparing means.The delaying means is coupled between the receiving means and thecombining means. The despreading means is coupled between the combiningmeans and the generating means. The storing means is coupled between thegenerating means and the comparing means, and the comparing means iscoupled to the delaying means.

The receiving means of FIG. 1 receives a spread-spectrum signal and aphased version of the spread-spectrum signal. The term "phased version"as used herein includes a version of the spread-spectrum signal having aphase different from the received spread-spectrum signal, and/or aversion of the spread-spectrum signal having a time delay with respectto the received spread-spectrum signal. The different phase and/or timedelay arises, as shown in FIG. 2, from the spread-spectrum signal 15 andthe phased version of the spread-spectrum signal 16 arriving fromdifferent paths, such as bouncing off different buildings 17, 18. Thephased array spread-spectrum system may be implemented at a base stationor, as shown in FIG. 2, at a remote subscriber unit (RSU) such as ahandset 19. The phase change occurs upon each reflection, since a firstspread-spectrum signal 15 has one reflection and a second ray, such asthe phased version of the spread-spectrum signal 16, has tworeflections. As a result of the difference in time between the twosignals, the multipath signals can undergo phase cancellation and causea fade. The phased array spread-spectrum system of FIG. 1 delays orphase shifts one of the two antennas 11, 12 enough to steer the beamfrom the two antennas to either building, or ray path having maximumsignal strength.

Typically, the receiving means, as shown in FIG. 1, includes a firstantenna 11 and a second antenna 12. The spread-spectrum signald(t)g(t)cosω₀ t is received with a first receiver coupled to the firstantenna 11, and the phased version of the spread-spectrum signald(t-τ)g(t-τ)cosω₀ (t-τ) is received with a second receiver coupled tothe second antenna 12. The first receiver and the second receiverinclude radio frequency (RF) and intermediate frequency (IF) amplifiersand filters, as appropriate. The received spread-spectrum signal and thephased version of the spread-spectrum signal may be digitized.

The delaying means, shown in FIG. 1 as a delay device 13, can delay thereceived spread-spectrum signal with respect to the phased version ofthe spread-spectrum signal by a delay. The received spread-spectrumsignal consequently becomes a delayed signal, with the delayapproximately equal to a delay of the phased version of thespread-spectrum signal. A preferred embodiment employs digital signalprocessing. Accordingly, the delaying means would include a digitaldelay device such as a shift register. Alternatively, analog circuitrywould employ an analog delay device, or a phase shifter.

Although illustrated with two antennas, the receiving means may includeadditional antennas for enhanced performance. The delaying means wouldhave appropriate delaying circuits to accommodate the multiple antennas.

The combining means, shown in FIG. 1 as a combiner 14, combines thedelayed signal and the phased version of the spread-spectrum signal as acombined signal. The delayed signal and the phased version of thespread-spectrum signal have approximately the same phase or time delay.Thus, an in-phase component of the delayed signal combines with anin-phase component of the phased version of the spread-spectrum signal,and a quadrature-phase component of the delayed signal combines with aquadrature-phase component of the phased version of the spread-spectrumsignal.

The despreading means despreads the combined signal as a despreadsignal. This may be accomplished using a product detector with achipping sequence matched to the received spread-spectrum signal, or amatched filter such as a surface acoustic wave (SAW) device having animpulse function matched to the chipping sequence of the receivedspread-spectrum signal. Product detectors, digital signal processors andSAW devices for despreading spread-spectrum signals are well known inthe art.

The generating means generates a magnitude value from the despreadsignal. The magnitude value may be an absolute value, the square of thein-phase component and quadrature-phase component of the despreadsignal, or other metric of the despread signal for determining arelative signal strength value. A magnitude value currently beinggenerated by the generating means is referred to herein as apresent-magnitude value. A magnitude value previously generated by thegenerating means is referred to herein as a previous-magnitude value.The invention is taught with the previous-magnitude value beinggenerated just before the present-magnitude value, although aprevious-magnitude value may be separated in time and other magnitudevalues from the present magnitude value. Also, more than oneprevious-magnitude value may be used. The concept of the presentinvention is taught with one previous-magnitude value.

The storing means stores the previous-magnitude value previouslygenerated by the generating means and the present-magnitude valuepresently generated by the generating means. In a digitalimplementation, the storing means might be embodied as a shift registeror, equivalently, as gates for performing the storing function. In ananalog implementation, the storing means might be embodied as two ormore capacitors for storing the previous-magnitude value and thepresent-magnitude value.

The previous-magnitude value and the present-magnitude value arecompared by the comparing means. In response to this comparison, thecomparing means outputs a comparison signal. The comparing means, forexample, may output a comparison signal to increase the delay τ of thedelaying means, if the present-magnitude value were greater than theprevious-magnitude value; conversely, the comparing means may output acomparison signal to decrease the delay τ of delaying means, if thepresent-magnitude value were less than the previous-magnitude value. Thedelaying means changes the first delay based on the comparison signal.If a plurality of previous-magnitude values were used, then a scheme maybe implemented with the comparing means to weight the plurality ofprevious-magnitude values.

The present invention provides improvement if the delay τ is less thanthe time of a chip T_(c). The present invention works on in-closemultipath. For far-out multipath, noise is produced. Thus, the presentinvention finds applications in buildings or within areas where τ<T_(c).For τ>T_(c) a RAKE system should be used.

In the exemplary arrangement shown in FIG. 3, the receiving means isembodied as the first antenna 11, a first RF/IF section 21, a firstanalog-to-digital converter 23, the second antenna 12, a second RF/IFsection 22, and a second analog-to-digital converter 24. The first RF/IFsection 21 is coupled between the first antenna 11 and the firstanalog-to-digital converter 23. The second RF/IF section 22 is coupledbetween the second antenna 12 and the second analog-to-digital converter24. Typically, the first RF/IF section 21 generates an in-phasecomponent and a quadrature-phase component of the receivedspread-spectrum signal. The second RF/IF section 22 generates anin-phase component and quadrature-phase component of the phased-versionof the spread-spectrum signal.

As illustratively shown in FIG. 3, the outputs of the firstanalog-to-digital converter 23 and the second analog-to-digitalconverter 24 may go to other sections for processing different channelsof the spread spectrum signal 25, 26.

The delaying means is embodied as a first digital delay device 27. Thedelaying means additionally may include a second digital delay device28. The first digital delay device 27 is coupled to the firstanalog-to-digital converter 23. If a second digital delay device 28 wereemployed, then the second digital delay device 28 is coupled to thesecond analog-to-digital converter 24.

The combining means is embodied as a first summer 29 and a second summer30. The first summer 29 is coupled to the first digital-delay device 27and to the second digital-delay device 28. The second summer 30 iscoupled to the first digital-delay device 27 and to the seconddigital-delay device 28. If the second digital delay device 28 were notemployed, then the first summer 29 is coupled to the first digital-delaydevice 27 and to the second analog-to-digital converter 24, and thesecond summer 30 is coupled to the first digital-delay device 27 and tothe second analog-to-digital converter 24.

The despreading means is embodied as a despreader 31. The despreader 31may be embodied as a product device coupled to an appropriatechipping-sequence generator and synchronization circuitry fordespreading the received spread spectrum signal. Alternatively, thedespreader 31 may be a digital signal processor which includes theappropriate product devices, or a matched filter having an impulseresponse matched to the chipping sequence of the received spreadspectrum signal. As is well known in the art, a surface acoustic wave(SAW) device having an impulse response matched to the chipping sequencemay be employed.

The generating means is embodied as a magnitude device 32. The magnitudedevice 32 is coupled to the despreader 31. Normally, the despreader 31is coupled to additional circuitry for demodulating data embedded in thereceived spread spectrum signal.

The storing means is embodied as a shift register 33. The shift register33 is coupled to the magnitude device 32. The storing meansalternatively may be embodied as a plurality of gates, registers, orother circuitry for storing magnitude values.

The comparing means may be embodied as a comparator 34 and an up/downcounter 35. The comparator 34 typically has two inputs coupled to theshift register 33. The up/down counter 35 is coupled to the output ofthe comparator 34 and to the first digital-delay device 27 and/or thesecond digital-delay device 28.

The first antenna 11 receives the spread-spectrum signal which isamplified by the first RF/IF section 21. The first RF/IF section 21outputs an in-phase component and a quadrature-phase component to thefirst analog-to-digital converter 23. The first analog-to-digitalconverter 23 converts the in-phase component and the quadrature-phasecomponent to a digitized in-phase component and a digitizedquadrature-phase component. These components may be processed by modulessimilar to the phase compensation circuitry 40, by coupling to theoutputs of the first analog-to-digital converter 23 at the outputs 25.

Similarly, a phased version of the spread-spectrum signal is received bythe second antenna 12 and then amplified and filtered by the secondRF/IF section 22. The second RF/IF section 22 has outputs for anin-phase component and a quadrature-phase component which are fed to thesecond analog-to-digital converter 24. The outputs 26 of the secondanalog-to-digital converter can go to modules similar to the phasecompensation circuitry 40 for processing different chipping sequences.For example, a spread spectrum signal may have a plurality ofspread-spectrum channels, with each spread-spectrum channel defined by adifferent chipping sequence. Accordingly, each module 40 would be usedfor a corresponding spread-spectrum channel, for processing with thatparticular chipping sequence.

The first digital-delay device 27 delays the digitized spread-spectrumsignal by a first delay. The output of the first digital-delay device 27is the first delayed signal. The second digital-delay device 28 delaysthe digitized phased version of the spread-spectrum signal by a seconddelay. The output of the second digital-delay device 28 is a seconddelayed signal. The second digital-delay device 28 is optional, and isnot required for use of the present invention. If the seconddigital-delay device 28 were not employed, then the term "second delayedsignal" refers to the digitized phased version of the spread-spectrumsignal, outputted from the second analog-to-digital converter 24.

The first summer 29 combines the quadrature-phase components of thefirst delayed signal from the first digital-delay device 27, with thequadrature-phase components of the second delayed signal from the seconddigital-delay device 28. The output of the first summer 29 is a firstcombined signal.

The second summer 30 combines an in-phase component from the firstdigital-delay device 27, with an in-phase component from the seconddigital-delay device 28. Accordingly, the in-phase components of thefirst delayed signal and the second delayed signal are combined as asecond combined signal.

The despreading device 31 despreads the first combined signal and thesecond combined signal as a despread quadrature-phase signal and adespread in-phase signal, respectively. The despread in-phase signal andthe despread quadrature-phase signal can be processed by furtherprocessing devices, not shown, for demodulating data embedded in thereceived spread-spectrum signal.

The magnitude device 32 generates a magnitude value from the despreadin-phase signal and the despread quadrature-phase signal. The magnitudevalue may be an absolute value determined from the despread in-phasesignal and the despread quadrature-phase signal, or a square of thedespread in-phase signal plus a square of the despread quadrature-phasesignal. Other metrics may be used for accomplishing the same function ofdetermining a relative signal strength value. The function of themagnitude value is to compare the signal strength of a present-magnitudevalue with a previous-magnitude value.

The shift register 33 stores the previous-magnitude value and thepresent-magnitude value in order that a comparison may be made by thecomparator 34. The comparator 34, when comparing the previous-magnitudevalue with the present-magnitude value, outputs a comparison signal. Thecomparison signal can control the up/down counter 35 to increase ordecrease a delay of the first digital-delay device 27. Optionally, theup/down counter 35 may increase or decrease a second delay of the seconddigital-delay device 28.

The present invention also includes a method for maximizing signalstrength of a spread-spectrum signal with multipath comprising the stepsof receiving the spread-spectrum signal and a phased version of thespread-spectrum signal. The in-phase and quadrature-phase components ofthe received spread-spectrum signal are delayed with respect to thein-phase and quadrature-phase components of the phased version of thespread-spectrum signal by a delay, to generate a delayed signal. Thein-phase component and the quadrature-phase component of the delayedsignal and the in-phase component and the quadrature-phase component ofthe phased version of the spread-spectrum signal are combined,respectively, as the in-phase component and quadrature-phase componentof a combined signal, and the combined signal is despread as an in-phasecomponent and a quadrature-phase component of a despread signal.

The method includes generating a magnitude value from the in-phasecomponent and the quadrature-phase component of the despread signal, andstoring a previous-magnitude value and a present-magnitude value. Theprevious-magnitude value and the present-magnitude value are compared,and a comparison signal is output based on this comparison. Using thecomparison signal, the delay is changed.

Base Station

The present invention may be extended to the base station, with theunique phased array spread-spectrum system processing a plurality ofspread-spectrum signals. In this embodiment, the receiving means receivea plurality of spread-spectrum signals and a plurality of phasedversions of the plurality of spread-spectrum signals. As shown in FIG.2, the different phases and\or time delays arise from thespread-spectrum signal 15 and the phased version of the spread-spectrumsignal 16 arriving from different paths, such as bouncing off differentbuildings 17, 18. Typically, the receiving means, as shown in FIGS. 3,4, and 5, includes the first antenna 11 and second antenna 12. Thereceiving means may further include appropriate RF and IF amplifiers andfilters. The received plurality of spread-spectrum signals and thereceived plurality of phased versions of the plurality ofspread-spectrum signals may be digitized.

The delaying means, shown in FIG. 4 as delay device 121, delay device122, . . . , delay device 123, can delay the received plurality ofspread-spectrum signals, with respect to the received plurality ofphased versions of the plurality of spread-spectrum signals, by aplurality of delays, respectively. The received plurality ofspread-spectrum signals consequently become a plurality of delayedsignals, with the delay for each of the plurality of delayed signalsapproximately equal to a delay of the respective phased version of thereceived spread-spectrum signal. A preferred embodiment would includedigital signal processing. Accordingly, the delay means would include adigital delay device such as a shift register. Alternatively, analogcircuitry would employ an analog delay device, or phase shifter.

The combining means, shown in FIG. 4 as a combiner 14, combines theplurality of delayed signals and the plurality of phased versions of theplurality of spread-spectrum signals as a combined signal. The output ofthe combining means may include appropriate RF circuitry and/or IFcircuity 124.

Each of the plurality of the delayed signals, and each of the respectivephased versions of the plurality of spread-spectrum signals,respectively, have the same phase or time delay. Thus, an in-phasecomponent of the delayed signal combines with an in-phase component ofthe phased version of a spread-spectrum signal, and a quadrature-phasecomponent of the delayed signal combines with a quadrature-phasecomponent of the phased version of the spread-spectrum signal.

The despreading means despreads the combined signal as a plurality ofdespread signals. This may be accomplished, as shown in FIG. 4, using aplurality of despreading devices, 131, 132, . . . , 133. Eachdespreading device may be implemented using a product detector or mixerwith a chipping sequence matched to the received spread-spectrum signalfor a particular channel. Alternatively, the despreader may beimplemented using a matched filter, such as surface acoustic wavedevice, having an impulse function matched to the chipping sequence ofthe received spread-spectrum signal for the particular channel. Productdetectors, mixers, digital signal processors and SAW devices fordespreading spread-spectrum signal are well known in the art.

The controller means changes the plurality of delays of the delay means,in response to the plurality of despread signals. The controlling means,as illustrated in FIG. 4, is embodied as a plurality of controlcircuitry 141, 142, . . . , 143. The controlling means outputs aplurality of comparison signals to the plurality of delay devices 121,122, . . . , 123.

The controlling means may include generating means, storing means, andcomparing means. The generating means can generate a plurality ofmagnitude values from the plurality of despread signals. The storingmeans stores a plurality of previous-magnitude values and a plurality ofpresent-magnitude values generated by the generating means. Thecomparing means compares the plurality of previous-magnitude values withthe plurality of present-magnitude values, and outputs a plurality ofcomparison signals. An embodiment of the generating means storing meansand comparing means is illustrated in FIG. 3.

In response to the plurality of comparison signals, the delay meanschanges the plurality of delays, respectively. FIG. 4 broadlyillustrates how the control circuitry 141, 142, . . . , 143 is coupledto the delay device 121, 122, . . . , 123, respectively. As apparent toone skilled to the art, the control circuitry shown in FIG. 4 may beimplemented using circuitry in FIG. 3 for each spread spectrum channel.

FIG. 5 illustrates an alternative embodiment, with a signal delay device13 coupled to the antenna 11. Also shown is an RF/IF amplifier 21coupled through the delay device 13 to the antenna 11, and an RF/IFamplifier 22 coupled to the antenna 12. In FIG. 5 each spread spectrumchannel, defined by chipping sequences g₁ (t), g₂ (t), . . . , g_(k)(t), is despread by the plurality of despreaders 151, 152, . . . , 153for the plurality of spread-spectrum channels. Similarly, the pluralityof phased versions of the plurality of spread-spectrum channels aredespread by the plurality of despreaders 161, 162, . . . , 163, usingchipping sequences g₁ (t), g₂ (t), . . . , g_(k) (t).

The delay device 13 delays the plurality of spread-spectrum signals withrespect to the received plurality of phased versions of the plurality ofspread-spectrum signals by a delay, thereby generating the plurality ofdelayed signals.

The combiner 153 combines the plurality of delayed signals and theplurality of phased versions of the spread-spectrum signals as acombined signal. In response to the combined signal, the controlcircuitry 166 changes the delay of the delay device 13.

In use, the phased array spread-spectrum system and method may be usedat a base station or a remote unit. A spread-spectrum signal beingreceived by the phased array spread spectrum system and method isreceived by the first antenna 11 and the second antenna 12, processed bythe first and second RF/IF sections 21, 22, and converted to a digitalform by first analog-to-digital converter 23 and secondanalog-to-digital converter 24. Preferably, digital signal processing isused and may be embodied in an application-specific integrated circuit(ASIC). The digitized spread-spectrum signal from the firstanalog-to-digital converter 23 is preferably delayed with respect to thedigitized phased version of the spread-spectrum signal from the secondanalog-to-digital converter 24. The first digital-delay device 27 isadjusted by an up/down counter 35 until the phase and/or time delaybetween the digitized spread-spectrum signal, and the digitized phasedversion of the spread-spectrum signal, are more closely aligned. Thealignment accrues due to the variations of the up/down counter 35 inresponse to comparisons by the comparator 34 of a present-magnitudevalue and a previous-magnitude value stored in register 33.

Thus, the spread-spectrum signal and a phased version of thespread-spectrum signal are received, processed to an intermediatefrequency or base band, and digitized. In-phase and quadrature-phasecomponents are used and delayed and added. The resulting in-phasecomponent and quadrature-phase component are then despread. Themagnitude of the despread spread-spectrum signal is then taken; thisrepresents the power or signal strength of the desired signal. Thepresent-magnitude value and the previous-magnitude value are input tothe shift register 33 and compared by the comparator 34. The comparator34 tells the up/down counter 35 to count as an increase or decrease,i.e., up or down, thereby controlling the delay. Thus, an increase incount might increase the delay, whereas a decrease in count woulddecrease the delay. Various control algorithms may be used with theup/down counter 35, for more efficiency.

The phased array spread-spectrum system steers an antenna beam formed bythe first antenna 11 and the second antenna 12 in the direction of thestrongest multipath. This function can be performed continually, so asto be continually looking for the optimal multipath. This beam steeringcan be done at a base station and at a handset, i.e, a remote subscriberunit.

It will be apparent to those skilled in the art that variousmodifications can be made to the base station phased array spreadspectrum system and method of the instant invention without departingfrom the scope or spirit of the invention, and it is intended that thepresent invention cover modifications and variations of the base stationphased array spread spectrum system and method provided they come withinthe scope of the appended claims and their equivalents.

I claim:
 1. A method for receiving a spread-spectrum signal comprisingthe steps of:receiving a plurality of spread-spectrum signals; receivinga phased versions of the plurality of spread-spectrum signals; delayingin-phase and quadrature components of the plurality of spread-spectrumsignals by a first plurality of delays, thereby generating a firstplurality of delayed signals; delaying in-phase and quadraturecomponents of the phased version of the plurality of spread-spectrumsignals by a second plurality of delays, thereby generating a secondplurality of delayed signals; combining quadrature components of thefirst plurality of delayed signals with respective quadrature componentsof the second plurality of delayed signals as a first plurality ofcombined signals; combining in-phase components of the first pluralityof delayed signals with respective in-phase components of the secondplurality of delayed signals as a second plurality of combined signals;despreading the first plurality of combined signals and the secondplurality of combined signals as a plurality of despread signals;generating a plurality of magnitude values of the plurality of despreadsignals; storing the plurality of magnitude values as a plurality ofpresent-magnitude values; comparing a plurality of previous-magnitudevalues with the plurality of present-magnitude values; outputting, inresponse to comparing the plurality of previous-magnitude values withthe plurality of present-magnitude values, a plurality of comparisonsignals; and changing, in response to the plurality of comparisonsignals, the first plurality of delays.
 2. The method as set forth inclaim 1 further, comprising the step of:changing, in response to theplurality of comparison signals, the second plurality of delays.
 3. Amethod for receiving a spread-spectrum signal comprising the stepsof:receiving a plurality of spread-spectrum signals; receiving a phasedversion of the plurality of spread-spectrum signals; delaying theplurality of spread-spectrum signals by a first plurality of delays,thereby generating a first plurality of delayed signals; delaying thephased version of the plurality of spread-spectrum signals by a secondplurality of delays, thereby generating a second plurality of delayedsignals; combining components of the first plurality of delayed signalswith respective components of the second plurality of delayed signals asa plurality of combined signals; despreading the plurality of combinedsignals as a plurality of despread signals; generating a plurality ofmagnitude values of the plurality of despread signals; comparing aplurality of previous-magnitude values with the plurality of magnitudevalues; and changing, in response to comparing the plurality ofprevious-magnitude values with the plurality of magnitude values, thefirst plurality of delays.
 4. The method as set forth in claim 3,further comprising the step of:changing, in response to comparing theplurality of previous-magnitude values with the plurality of magnitudevalues, the second plurality of delays.
 5. The method as set forth inclaim 3, further comprising the step of:storing the plurality ofmagnitude values as the plurality of previous-magnitude values.
 6. Amethod for receiving a spread-spectrum signal comprising the stepsof:receiving a spread-spectrum signal; receiving a phased version of thespread-spectrum signal; delaying the spread-spectrum signal by a firstdelay, thereby generating a first delayed signal; delaying the phasedversion of the spread-spectrum signal by a second delay, therebygenerating a second delayed signal; combining the first delayed signaland the second delayed signal as a combined signal; despreading thecombined signal as a despread signal; generating a magnitude value ofthe despread signal; comparing a previous-magnitude value with themagnitude value; and changing, in response to comparing theprevious-magnitude value with the magnitude value, the first delay. 7.The method as set forth in claim 6, further comprising the stepof:changing, in response to comparing the previous-magnitude value withthe magnitude value, the second delay.
 8. The method as set forth inclaim 6, further comprising the step of:storing the magnitude value asthe previous-magnitude value.
 9. The method as set forth in claim 8,further comprising, after the step of storing, the step of repeating thesteps of claim 6.